Sun Microelectronics
51
6. MMU Internal Architecture
•
Attempted access using a restricted ASI in non-privileged mode. The MMU
signals a
privileged_action
exception for this case.
•
An atomic instruction (including 128-bit atomic load) issued to a memory
address marked uncacheable in a physical cache (that is, with CP=0),
including cases in which the D-MMU is disabled. The MMU signals a
data_access_exception
trap (FT=04
16
) for this case.
•
A data access (including FLUSH) with an ASI other than
ASI_{PRIMARY,SECONDARY}_NO_FAULT{_LITTLE} to a page marked with
the NFO (no-fault-only) bit. The MMU signals a
data_access_exception
trap
(FT=10
16
) for this case.
•
Virtual address out of range (including FLUSH) and PSTATE.AM is not set.
The MMU signals a
data_access_exception
trap (FT=20
16
) for this case.
Table 6-4
D-MMU Operations for Normal ASIs
Condition
Behavior
Opcode
PRIV
Mode
ASI
W
TLB
Miss
E=0
P=0
E=0
P=1
E=1
P=0
E=1
P=1
Load
0
PRIM, SEC
—
DMISS
OK
DEXC
OK
DEXC
PRIM_NF, SEC_NF
—
DMISS
OK
DEXC
DEXC
DEXC
1
PRIM, SEC, NUC
—
DMISS
OK
OK
PRIM_NF, SEC_NF
—
DMISS
OK
DEXC
U_PRIM, U_SEC
—
DMISS
OK
DEXC
OK
DEXC
FLUSH
0
—
DMISS
OK
DEXC
DEXC
DEXC
1
—
DMISS
OK
OK
DEXC
DEXC
Store or
Atomic
0
PRIM, SEC
0
DMISS
DPROT
DEXC
DPROT
DEXC
1
DMISS
OK
DEXC
OK
DEXC
1
PRIM, SEC, NUC
0
DMISS
DPROT
DPROT
1
DMISS
OK
OK
U_PRIM, U_SEC
0
DMISS
DPROT
DEXC
DPROT
DEXC
1
DMISS
OK
DEXC
OK
DEXC
—
0
BYPASS
—
privileged_action
—
1
BYPASS
—
Bypass. No traps when D-MMU enabled,
PRIV=1.
Table 6-5
I-MMU Operations for Normal ASIs
Condition
Behavior
PRIV Mode
TLB Miss
P=0
P=1
0
IMISS
OK
IEXC
1
IMISS
OK
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